Typically, at least in EU, heating systems are regulated per unit in condos, meaning you can choose how much water you allow to flow in the local dissipator/hea

Typically, at least in EU, heating systems are regulated per unit in condos, meaning you can choose how much water you allow to flow in the local dissipator/heat exchanger, so the fact there is a single source of heat does not means individuals have to heat too much or too little. The central heater have a job: keep hot water at a certain temperature, the distribution system have a job: keep hot water flowing at a certain rate, so you can get more or less water per unit issueless (at least in a certain range, projected up front where pumps are dimensioned), individual thermostat valves have a job decide how much water have to flown locally in an apartment or depending on the heating element per-room. The issue happen with badly designed systems. There was an era in the '60s where heating fuel (oil at that time) was so cheap that builders decide it was cheaper to heat much and open the windows as needed instead of design a proper system with margins. Back than there was not much climate analysis when you project a new building. Most condos was built just for speculation, with little attention to the tech. Most buyers do not care much even today.